Improved Reflectarray Feeds Using Gradient Index Lenses

Reflectarray antenna (RA) systems are being increasingly used in many applications due to the advantages of their simple design and spatial feeding along with their capabilities for beam shaping and beam forming. However, like all aperture antennas, RAs are limited in the maximum gain they can achieve and power handling they can attain as a result of the feed illumination. By augmenting an RA horn feed with a GRadient INdex (GRIN) lens it is shown that it is possible to better distribute the feed's incident illumination across the surface while still maintaining the gain of the nominal system. Specifically, this work demonstrates that a GRIN lens designed for an offset fed RA at S Band operation can reduce the peak field strength by 17.6
^%
and correspondingly improve the power handling capability by 47% relative to the nominal, no-lens system.